Proposal and analysis of a high-efficiency combined desalination and refrigeration system based on the LiBr–H2O absorption cycle—Part 1: System configuration and mathematical model

2011 ◽  
Vol 52 (1) ◽  
pp. 220-227 ◽  
Author(s):  
Yongqing Wang ◽  
Noam Lior
Keyword(s):  
Mathematical Model ◽  
High Efficiency ◽  
Refrigeration System ◽  
System Configuration ◽  
Absorption Cycle

scholarly journals Comprehensive Parameters Identification and Dynamic Model Validation of Interior-Mount Line-Start Permanent Magnet Synchronous Motors

Machines ◽  
2019 ◽  
Vol 7 (1) ◽  
pp. 4 ◽  
Author(s):  
Luqman S. Maraaba ◽  
Zakariya M. Al-Hamouz ◽  
Abdulaziz S. Milhem ◽  
Ssennoga Twaha
Keyword(s):  
Mathematical Model ◽  
Permanent Magnet ◽  
High Efficiency ◽  
Experimental Tests ◽  
Induction Machines ◽  
Test Methods ◽  
Operating Conditions ◽  
Test Method ◽  
Permanent Magnet Synchronous Motors ◽  
Synchronous Motors

The application of line-start permanent magnet synchronous motors (LSPMSMs) is rapidly spreading due to their advantages of high efficiency, high operational power factor, being self-starting, rendering them as highly needed in many applications in recent years. Although there have been standard methods for the identification of parameters of synchronous and induction machines, most of them do not apply to LSPMSMs. This paper presents a study and analysis of different parameter identification methods for interior mount LSPMSM. Experimental tests have been performed in the laboratory on a 1-hp interior mount LSPMSM. The measurements have been validated by investigating the performance of the machine under different operating conditions using a developed qd0 mathematical model and an experimental setup. The dynamic and steady-state performance analyses have been performed using the determined parameters. It is found that the experimental results are close to the mathematical model results, confirming the accuracy of the studied test methods. Therefore, the output of this study will help in selecting the proper test method for LSPMSM.

scholarly journals Numerical Simulation of a New Porous Medium Burner with Two Sections and Double Decks

Processes ◽  
2018 ◽  
Vol 6 (10) ◽  
pp. 185 ◽  
Author(s):  
Zhenzhen Jia ◽  
Qing Ye ◽  
Haizhen Wang ◽  
He Li ◽  
Shiliang Shi
Keyword(s):  
Numerical Simulation ◽  
Mathematical Model ◽  
Porous Medium ◽  
Industrial Development ◽  
High Efficiency ◽  
Methane Combustion ◽  
Combustion Mechanism ◽  
Gas Mixture ◽  
Temperature And Pressure ◽  
Save Energy

Porous medium burners are characterized by high efficiency and good stability. In this study, a new burner was proposed based on the combustion mechanism of the methane-air mixture in the porous medium and the preheating effect. The new burner is a two-section and double-deck porous medium with gas inlets at both ends. A mathematical model for the gas mixture combustion in the porous medium was established. The combustion performance of the burner was simulated under different equivalence ratios and inlet velocities of premixed gas. The methane combustion degree, as well as the temperature and pressure distribution, was estimated. In addition, the concentrations of emissions of NOx for different equivalence ratios were investigated. The results show that the new burner can not only realize sufficient combustion but also save energy. Furthermore, the emission concentration of NOx is very low. This study provides new insights into the industrial development and application of porous medium combustion devices.

scholarly journals Economic Analysis of Solar Refrigeration and Desalination System

2019 ◽  
Vol 118 ◽  
pp. 02021
Author(s):  
Xiaoman Zhang ◽  
Qin Shen ◽  
Shijun Zhu
Keyword(s):  
Mathematical Model ◽  
Economic Analysis ◽  
Physical Model ◽  
Energy Supply ◽  
Recovery Period ◽  
Heat Consumption ◽  
Refrigeration System ◽  
Generation System ◽  
Refrigeration Capacity ◽  
Solar Refrigeration

The physical model and mathematical model of solar refrigeration and desalination co-generation system were established. The performance and economy of the system were analyzed by changing the three variables of refrigeration capacity, seawater desalination effects number and three different cities. The results show that increasing refrigeration capacity is conducive to improving freshwater production and increasing freshwater efficiency, but more auxiliary heat consumption is needed, the comprehensive effect is to shorten the recovery period. Increasing desalination efficiency is conducive to increasing freshwater production and freshwater efficiency, and the auxiliary heat consumption remains unchanged. The comprehensive effect is to shorten the recovery period. Solar energy is the main energy needed in the co-generation system of the three cities, and Shenzhen has the largest proportion of energy supply, which reaches 67.8%. Compared with the solar refrigeration system, the recovery period of the co-generation system can bu shortened by 18.1%.

Regenerative Gas Turbines With Divided Expansion

2004 ◽  
Author(s):  
Brian Elmegaard ◽  
Bjo̸rn Qvale
Keyword(s):  
Mathematical Model ◽  
Gas Turbines ◽  
High Efficiency ◽  
Limited Range ◽  
Simulation Program ◽  
Operating Parameters ◽  
Gas Generator ◽  
Extensive Simulation ◽  
Power Turbine ◽  
The Mathematical Model

Recuperated gas turbines are currently drawing an increased attention due to the recent commercialization of micro gas turbines with recuperation. This system may reach a high efficiency even for the small units of less than 100kW. In order to improve the economics of the plants, ways to improve their efficiency are always of interest. Recently, two independent studies have proposed recuperated gas turbines to be configured with the turbine expansion divided, in order to obtain higher efficiency. The idea is to operate the system with a gas generator and a power turbine, and use the gas from the gas generator part for recuperation ahead of the expansion in the power turbine. The present study is more complete than the predecessors in that the ranges of the parameters have been extended and the mathematical model is more realistic using an extensive simulation program. It is confirmed that the proposed divided expansion can be advantageous under certain circumstances. But, in order for todays micro gas turbines to be competitive, the thermodynamic efficiencies will have to be rather high. This requires that all component efficiencies including the recuperator effectiveness will have to be high. The advantages of the divided expansion manifest themselves over a rather limited range of the operating parameters, that lies outside the range required to make modern micro turbines economically competitive.

scholarly journals Fault diagnosis of air-conditioning refrigeration system based on sparse autoencoder

2019 ◽  
Vol 14 (4) ◽  
pp. 487-492
Author(s):  
Zhiyi Wang ◽  
Jiachen Zhong ◽  
Jingfan Li ◽  
Cui Xia
Keyword(s):  
Fault Diagnosis ◽  
Air Conditioning ◽  
Large Scale ◽  
High Efficiency ◽  
Support Vector ◽  
Small Scale ◽  
Refrigeration System ◽  
Large Scale Data ◽  
Fault Features ◽  
Sparse Autoencoder

Abstract To overcome the drawbacks of using supervised learning to extract fault features for classification and low nonlinearity of the features in most of current fault diagnosis of air-conditioning refrigeration system, sparse autoencoder (SAE) is presented to extract fault features that are used as the input to the classifier and to achieve fault diagnosis for air-conditioning refrigeration system. The SAE structure is tuned by adjusting the number of hidden layers and nodes to build the optimal model, which is compared with the fault diagnosis model based on support vector machine. Results indicate that the indexes of the model combined with SAE, such as accuracy, precision and recall, are all improved, especially for the faults with high complexity. Besides, SAE shows high generalization ability with small-scale sample data and high efficiency with large-scale data. Obviously, the use of SAE can effectively optimize the diagnosis performance of the classifier.

scholarly journals C2 Continuous Blending of Time-Dependent Parametric Surfaces

2019 ◽  
Vol 19 (4) ◽  
Author(s):  
Xiangyu You ◽  
Feng Tian ◽  
Wen Tang
Keyword(s):  
Mathematical Model ◽  
Analytical Solution ◽  
High Efficiency ◽  
Approximate Analytical Solution ◽  
Time Dependent ◽  
Order Partial Differential Equation ◽  
Parametric Surfaces ◽  
Boundary Constraints ◽  
Surface Blending ◽  
C2 Continuity

Surface blending is widely applied in mechanical engineering. Creating a smooth transition surface of C2 continuity between time-dependent parametric surfaces that change their positions and shapes with time is an important and unsolved topic in surface blending. In order to address this issue, this paper develops a new approach to unify both time-dependent and time-independent surface blending with C2 continuity. It proposes a new surface blending mathematical model consisting of a vector-valued sixth-order partial differential equation and blending boundary constraints and investigates a simple and efficient approximate analytical solution of the mathematical model. A number of examples are presented to demonstrate the effectiveness and applications. The proposed approach has the advantages of (1) unifying time-independent and time-dependent surface blending, (2) always maintaining C2 continuity at trimlines when parametric surfaces change their positions and shapes with time, (3) providing effective shape control handles to achieve the expected shapes of blending surfaces but still exactly satisfy the given blending boundary constraints, and (4) quickly generating C2 continuous blending surfaces from the approximate analytical solution with easiness, good accuracy, and high efficiency.

Design and Analysis of Cooling Cabinet for Vaccine Storage

2014 ◽  
Vol 984-985 ◽  
pp. 1180-1183
Author(s):  
N. Saravanan ◽  
R. Rathnasamy ◽  
V. Ananchasivan
Keyword(s):  
Mathematical Model ◽  
Cooling Effect ◽  
Refrigeration System ◽  
Ansys Software ◽  
Adsorption Refrigeration ◽  
Ammonia Adsorption ◽  
Energy Demands ◽  
Solar Intensity ◽  
Solar Powered ◽  
The Impact

Solar powered adsorption refrigeration system is renewable source in the future energy demands and more useful for off-grid area. In this paper a mathematical model was developed to investigate the performance of a cooling cabinet of a activated carbon-ammonia adsorption refrigeration system, and a new effective method about the refrigeration studies. A brief thermodynamic study of the cooling cabinet is carried out and the effect of operating parameters such as temperature, pressure, cooling effect of the system is numerically analyzed. The impact of solar intensity on performance of the system is significant. The cooling cabinet model is completely analysied for varies capacity and it is able to calculate the cooling cabinet coil length .The designed mathematical model is analyzed by the use of coolpack software and the results are compared with ansys software. It is observed that the system operate more efficient while maximum solar intensity and the cooling effect. Key words: Solar, Adsorption Refrigeration, Mathematical model, Analysis, Solar intensity.

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